<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div id="app">
    <button v-on:click="sayHi">点我</button>
</div>

<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
    var vm = new Vue({
        el: '#app',
        data: {
            message: "杨琛"
        },
        methods: {
            sayHi: function (event) {
                alert(this.message);
            }
        }
    })

</script>
</body>
</html>